4.2.4 The Real-Time Scheduler

The real-time scheduler (Scheduler/RealTime../ns-2/scheduler.cc)
attempts to synchronize the execution of events with real-time.
It is currently implemented as a subclass of the list scheduler.
The real-time capability in ns is still under development, but is used
to introduce an ns simulated network into a real-world topology
to experiment with easily-configured network topologies, cross-traffic, etc.
This only works for relatively slow network traffic data rates, as the
simulator must be able to keep pace with the real-world packet arrival
rate, and this synchronization is not presently enforced.